PREDATOR 670cc MAIN JETS ISSUE, POSSIBLE REMEDY USING THE JETS THAT CAME WITH THE ORIGINAL ENGINE

Predator 670cc Main JETS Issues, possible remedy using spare jets that came with the engine DCTMAKES Harbor Freight predator 670cc... Different jets in the crate engine, change the exhaust to equal lengths and even up the jets
PREDATOR 670cc MAIN JETS issue, POSSIBLE REMEDY USING THE JETS THAT CAME WITH THE ORIGINAL ENGINE

[@paulliebenberg3410]

In addition to the different length exhaust paths, the un-even v-twin firing order will make a subtle difference in the fuel mixture between the cylinders.

[@quailman352]

this makes alot of sense to me as to why one side blows smoke like its rich on that side. you sir are a genus! im at sea level with basically straight pipes and Im gonna try the 105s first.

[@BobSmith-te6rf]

@4:38 - can confirm, you are 100% correct. I just unboxed my Predator 670, and verified that the 108 jet is on the Right (as marked on the carburetor with the R), and the 105 is on the left. So the description in this video is exactly correct, regarding the stock configuration. Thanks for uploading this explanation and suggested fixes. Subscribed.

[@mg-bx6bi]

brilliant. Only place I've seen this discussed. For my application I had to cut the exhaust pipes, then reverse the exhaust connections so it wasn't blowing straight into my back. My application is not a high performance need, so I doubt I'll ever do any more. Maybe some day :).

[@amidon422]

Thanks been back & forth with this predator 670 trying to get it to stop bogging & popping & even flooding sometimes!

[@paulcaruthers9647]

Thanks for posting this, very informative.

[@dctmakes3487]

Glad it was helpful!

[@steveblack276]

So i have changed the jets to 105 both sides and adjusted. It runs much better. So thanks for the info!! However sometimes the area in front of the intake pools up with fuel and other times floods. I have two carbs and they both seem to flood randomly.

[@dctmakes3487]

Few questions. Electric fuel pump with diaphragm pump removed or diaphragm pump by it self or electric then the diaphragm pump still in the fuel line ?? next equal length exhaust pipes or the stock cross over ?? does it do this at idle or full open or random?? these carbs are ridiculously baggy (loose) if the idle jets are standard, push the welch plugs out and play with a little leaner setup with the idle screws. note the weather, air pressure and lots of odd things can affect it. Old gas, plugs not burning clean etc etc the list is endless BUT 1 thing changed at a time then test or you will never find the issue .

[@steveblack276]

@@dctmakes3487 first try was an electric pump then with a pressure regulator then back to the original pulse pump then put in a briggs pulse pump. then a new carb. now im questioning fuel quality because ive been fooling around (in my spare time) for almost a year!! the exhaust is equal length with mini glass pack type mufflers. operation seems to be random. It will idle great for awhile and if i throttle up it will flood and die....sometimes.

[@dctmakes3487]

hallmarks of float and needle issues (being as your back on low pressure diaphragm) maybe some dirt floating around in the bowl holding the needle seat open for the flooding part then your plugs are probably fowled out. your going through all the same things I did. When it floods check the plugs immediately. just to be sure . best of luck intermittent stuff can be hard to find

[@TheLaserguy2]

So, due to my installation, I need to essentially reverse the exhaust direction. Instead of exiting the muffler as shown, I need it to exit from the other end. Okay, I am actually going to fab up a new exhaust header, but one leg will still be longer. And, I will be running at about 3500' elevation. So is it your suggestion that I remove the 108 and install the 102. And just leave the 105 where it is?

[@dctmakes3487]

Evening, you are correct, jets size follows the pipe length, based on original carb layout. You may have to further 102 and 98 but try what you said in your comment first

[@craigmitchell5628]

What would you recommend for the main jet sizes and the idle/low rpm jet sizes with straight pipes at low altitudes?

[@dctmakes3487]

Hi, I would say the sea level mains that come in it 108 and 105 get another 108 and then they are at least even , leave the low jets as they are again measure see if they are even .... question back how lower altitude, were are you at? its a interesting deal on how this would work

[@craigmitchell5628]

322' above sea level lower Alabama USA

[@dctmakes3487]

@@craigmitchell5628 well not much different than here, so 108's matched or the 105's matched, punch out the welch plugs on the idle screws and mess with them before you make the mistake I made drilling the idle jets out . the matched exhaust pipes, main jets matched will probably give you the best end result ... and its all cheap to do just time . One deal, make sure you go from cold to full engine heat on each change you make to make sure it works across the board.. Its no good starting up and idling but it pops and farts when it gets hot . and then wont start again

[@craigmitchell5628]

Thanks for the reply and your videos!! My predator is in an ezgo txt. I only have about 3 hrs of break-in time. I have already played with the idle jets adjustment. I had them backed out from closed to 2 1/2 turns. It cranked without choke and idled great around 1200 rpm. However it stumbles on fast acceleration. I then backed it out to about 4 turns and the stumble decreases. I can still idle at 1200 but it takes awhile for it to settle in. I have the governor spring tye wrapped. My goal is optimal throttle response, low idle, and borderline rich mixture. I watched your video on the governor override but since you changed carbs I don't know if it would work with mine. I can definitely feel the governor tugging against the throttle. Thanks again for your great videos !!!

[@dctmakes3487]

@@craigmitchell5628 one last piece, the carbs are almost identical so it would work, just some form of top rpm count delimiter. with the gov out of the picture the throttle response was much better . now thats due to me changing gears, if your using a torque converter it would be even better . depends on your setup. have a good day

[@psychosbuildsgaming4452]

So what jet should I run in my predator if I straight pipe them equal lengths about a foot an a half on Both pipes ?

[@dctmakes3487]

Morning, if your at sea level, start with the 105's on both, then see if that works for your application, if not step them up by drilling out ONLY one drill size at a time. They are about #59 drill so the next step #58. This all depends on application also, different issues between say a cart with the governor off and a stump grinder. Bigger point is keep the main jets the same then experiment

[@wisconsinbush2940]

Where did you get the jets?

[@dctmakes3487]

they come with the predator original purchase, for different elevations

[@darryllindsey6669]

Where did you order the jets from

[@dctmakes3487]

I used the ones that came with the engine, you get 6, base, 3000 and 6000 altitude . I just evened them up after pulling the exhaust. watch it through again I think you missed a piece

[@dctmakes3487]

kzbin.info/aero/PLAY6CHyC9I87QdxgzEVBR0Z3b8CJXLlH1&si=KZQd-o1O8Pd1V6OI kzbin.info/aero/PLAY6CHyC9I87_dTHlQVtQawXz5xDCJTa0&si=BOPK7FC-GbW4kreV